Abstract: Social networks, especially Facebook, currently as the largest one, have made the organization of events apparently simpler. Facebook offers the event service, which has greatly simplified the invitation process. Still, organizing an event is usually coupled with the risk of guest’s no-show. We report an investigation designed to identify factors that might help predict a person’s likelihood of attendance to an event s/he is invited to. Our research tries to combine information research with information technology tool design. The factors affecting the probability were determined by an analysis of data acquired in surveys among hundred and fifty or so Facebook users. We also developed a program that implements (some of) these findings. Simple quantitative and qualitative analyses were carried out on the data, sufficient to identify some of the key factors influencing invitees in their decision to attend a meeting. The factors as identified by the surveys are indeed relevant to attendance of meetings arranged using social media. Our application can help the event creator estimate how many people would attend his event and predict the likelihood of each invitee’s attendance. Moreover, the application can also help the invited guest learn which of his friends are likely to attend the same event. Research that combines information side with information technology side can be fruitful as shown by this simple result. There is room for future work in this interdisciplinary space.

Organizing meetings of more people has a difficulty every organizer knows about – one invites a few dozens of friends to an event and only a handful of them show up. Many of the invited guests even do not respond to the invitation by either confirming or declining their attendance. The issue becomes even more problematic when the event is a mass event, such as a demonstration, where estimations of attendance may reach hundreds or even tens of thousands.

Not a long time ago, to organize an event, such as a graduation class meeting, one had to call every classmate and tell him/her about the event. When an invited guest did not respond right away, the organizer had to either wait for the guest to call back or he could call him again some time later to remind the guest of the event. Another option was to send everyone a short text message with the invitation. However, it could be difficult to write everything important in a limited space.

Social networks, especially Facebook as currently the largest one, have become an important media for social communication (Young 2011). In particular, they made organizing of events much simpler. This is a very recent observation. Still in 2008, with the event function already available (Hei-man 2008), the use of Facebook to attend an event organized online was relatively infrequent type of use according to Joinson (2008). Nowadays, to organize a meeting, concert or other event, in which many people participate, one does not have to send a text message or an email to all guests. Letting people know about an event translates into just a few clicks on Facebook and all invited guests get notified about it. All invited guests can see who has responded to the invitation and how. However, even though the organization process has changed, it seems people have remained essentially the same and many of them still do not respond to some invitations at all, which is a problem for the

organizer, because he often needs to know at least the approximate number of guests, so that he can, for example set up a reservation in a pub or change the time of the event if not many people intend to attend the event.

The motivation of this work is to help the organizers to facilitate face-to-face meetings. Predictions of attendance are not only useful for setting up a reservation, but can also be used as a tool to better reach the invited guests and adjust the event in such a way (by inviting more guests or changing the location of the event) that more guests would attend. Using attendance predictions in this way has a huge potential not only in organizing parties, but also in organizing mass events or for advertising purposes.

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JOINSON, N., Looking At, looking Up or keeping Up with People?: Motives and Use of FACEBOOK, in Proceedings of the Twenty-Sixth Annual SIGCHI Conference on Human Factors in Computing Systems, series CHI.’08. New York, NY , USA: ACM, 2008, pp. 1027-1036.

MASLI, M., W. GEYER, C. DUGAN, B. BROWNHOLTZ, The Design and Usage of Tentative Events for Time-based Social Coordination in the Enterprise, in Proceedings of the 20th International Conference on World Wide Web, ser. WWW’11. New York, NY, USA: ACM, 2011, pp. 765-774.

BARKHUUS, L., J. TASHIRO, Student Socialization in the Age of FACEBOOK, in Proceedings of the 28th International Conference on Human Factors in Computing Systems, ser. CHI’10. New York, NY, USA: ACM, 2010, pp. 133-142.